Poker is a card game in which players bet chips (representing money) on the outcome of a hand. There are countless variants of poker, but they all share certain fundamentals. A poker hand comprises five cards; the value of a particular hand is in inverse proportion to its mathematical frequency, and poker games can be characterized by the amount of money that one player is willing to put at risk on the basis of his evaluation of that probability. Players may also bet in a bluffing fashion, trying to make other players call their bets when they believe that they have the best hand.

In most poker games, one or more players are required to place forced bets at the beginning of each betting round, usually an ante and a blind bet. Players then receive their cards, which they may or may not reveal. The cards are gathered into a central pot, and the player who has the highest-ranking poker hand according to the rules of the specific variant being played wins the pot.

In some poker variants, players take turns revealing their hands. This is called a showdown. The winning player claims the main pot and any side pots that have been created from raises. A player who is all-in cannot win the main pot, but can still win a side pot to which they have contributed. If a player folds, they give up all the money that they have bet in that round.